1. Field of the Invention
The present invention relates to a voice analysis method, a voice analysis device, a voice synthesis method, a voice synthesis device, and a computer readable medium storing a voice analysis program.
2. Description of the Related Art
There is proposed a technology for generating a time series of a feature amount of a sound by using a probabilistic model for expressing a probabilistic transition between a plurality of statuses. For example, in a technology disclosed in Japanese Patent Application Laid-open No. 2011-13454, a probabilistic model using a hidden Markov model (HMM) is used to generate a time series (pitch curve) of a pitch. A singing voice for a desired music track is synthesized by driving a sound generator (for example, sine-wave generator) in accordance with the time series of the pitch generated from the probabilistic model and executing filter processing corresponding to phonemes of lyrics. However, in the technology disclosed in Japanese Patent Application Laid-open No. 2011-13454, a probabilistic model is generated for each combination of adjacent notes, and hence probabilistic models need to be generated for a large number of combinations of notes in order to generate singing voices for a variety of music tracks.
Japanese Patent Application Laid-open No. 2012-37722 discloses a configuration for generating a probabilistic model of a relative value (relative pitch) between the pitch of each of notes forming a music track and the pitch of the singing voice for the music track. In the technology disclosed in Japanese Patent Application Laid-open No. 2012-37722, the probabilistic model is generated by using the relative pitch, which is advantageous in that there is no need to provide a probabilistic model for each of the large number of combinations of notes.